The invention relates to coatings with strong adhesion on arbitrarily chosen substrate materials, high hardness and high wear and corrosion resistance. These films increase the service life and improve the functional properties of the coated elements. Such elements are for example, tools, cutting inserts, bearings, or corrosive stressed elements.
Further applications can be expected in the fields of electronics and optics and also for decorative purposes. Hard coatings for mechanical and corrosive stressed elements in many cases are deposited by ion-assisted techniques. Different types of such deposition techniques are known. It depends on the special technical or scientific problem to be solved, which method is the most effective one.
In patent DD-WP No. 155826, hard coatings consisting of diamondlike carbon, metal components and carbides, nitrides, or borides are described. For the synthesis of carbides etc., high energies of generation or high temperatures are necessary. Commonly, for ion-assisted techniques, similar conditions must be chosen. Therefore, thermally sensitive elements can be coated only at high technical expense, or the coating of such elements impossible. For example are higher than 300.degree. C. and for chromium carbide phases higher than 1000.degree. C. (K. Bewilogua et al., Kristall and Technik 15 (1980) 1205). In patent DE-OS No. 3246361, a layer with excellent sliding properties consisting of a carbonmetal matrix described. However, a film of this type, having good sliding properties, does not fulfil the requirements of corrosion and wear resistance.
Furthermore, hard coatings on the basis of boron/nitrogen (B/N) are known (DD-WP No. 156717). The adhesion of such coatings, especially on metal substrates, is in many cases insufficient and must be improved by intermediate layers. In the described range of film thicknesses (0.2 . . . 2 .mu.m), a wear-reducing effect can be obtained only for small values of the normal load during the wear process.
All the described hard coatings exhibit high efficiency only in special fields of application, for instance as wear- or corrosion-resistive layers.